title: Four related diethyl [(arylamino)(4-ethynylphenyl)methyl]phosphonates.
abstract: Crystal structures are reported for four related diethyl [(arylamino)(4-ethynylphenyl)lmethyl]phosphonate derivatives, namely diethyl [(4-bromoanilino)(4-ethynylphenyl)methyl]phosphonate, C19H21BrNO3P, (I), diethyl ((4-chloro-2-methylanilino){4-[2-(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C23H31ClNO3PSi, (II), diethyl ((4-fluoroanilino){4-[2-(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C22H29FNO3PSi, (III), and diethyl [(4-ethynylphenyl)(naphthalen-2-ylamino)methyl]phosphonate, C23H24NO3P, (IV). The conformation of the anilinobenzyl group is very similar in all four compounds. The P-C bond has an approximately staggered conformation, with the aniline and ethynylphenyl groups in gauche positions with respect to the P=O double bond. The two six-membered rings are almost perpendicular. The sums of the valence angles about the N atoms vary from 344 (2) to 351 (2)°. In the crystal structures, molecules of (I), (III) and (IV) are arranged as centrosymmetric or pseudocentrosymmetric dimers connected by two N-H···O=P hydrogen bonds. The molecules of (II) are arranged as centrosymmetric dimers connected by C(methyl)-H···O=P hydrogen bonds. The N-H bond of (II) is not involved in hydrogen bonding.
authors.affiliation: Laboratory of Bioorganic and Macromolecular Chemistry, Department of Chemistry, Faculty of Sciences and Technology Guéliz (FSTG), BP 549, Marrakech, Morocco.
authors.forename: Abdelaaziz
authors.initials: A
authors.lastname: Ouahrouch
authors.forename: Jamal
authors.initials: J
authors.lastname: Krim
authors.forename: Moha
authors.initials: M
authors.lastname: Taourirte
authors.forename: Hassan B
authors.initials: HB
authors.lastname: Lazrek
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Engels
authors.forename: Jan W
authors.initials: JW
authors.lastname: Bats
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D009281:Naphthalenes; D063065:Organophosphonates; C587105:diethyl((4-bromoanilino)(4-ethynylphenyl)methyl)phosphonate; C587107:diethyl((4-ethynylphenyl)(naphthalen-2-ylamino)methyl)phosphonate
keywords: crystal structure; diethyl [(arylamino)(4-ethynylphenyl)methyl]phosphonates